Centralizer for drill steels



v y 8, 1930. c. c. HANSEN 1,769,921

CENTRALIZER FOR DRILL STEELS Filed Dec. 11, 1928 A' (I l' l HQ 6f INVENTOR.

' steel causes it to bind in the drill hole.

Patented July 8, 1930 STATES PATENT oFFica CHARLES C. HANSEN, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-ZBIAND COMPANY, OF JERSEY CITY, NEW JERSEY, A GORPORATION OF NEW JERSEY GENTRALIZER FOR DRILL STEELS Application filed December 11, 1928. Serial No. 325,141.

This invention relates to submarine drilling apparatus, but more particularly to a centralizer for drill steelsused for drilling submerged rock.

The object of the invention is to maintain the drill steel concentric with the sand pipe through which itextends, particularly when first spotting or starting the drill hole.

hen first starting a drill hole it is oftentimes a difficult matter to maintain the cutting end of the drill bit coaxial with the drilling apparatus. The free end of the drill steel tends to whip around its axis with the result that the hole may be started out of line of the drilling apparatus. The drill steel being flexible will then follow the original direction of out. In shallow holes this may not be serious, but where holes of considerable depth are being drilled the deflection of the (llllll T iis condition not infrequently results in breakage of the drill steel and in many instances it becomes necessary to abandon both the drill hole and the drill steel.

The present invention contemplates the elimination of an occurrence of this kind and aims to hold the drill steel concentrically with respect to thesand pipe until the drill hole is drilled to such a depth that the cutting bit of the drill will readily follow the desired line of out.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings illustrating the invention and in which similar reference characters refer to similar parts,

Figure l is a sectional elevation of a sand pipe and the centralizer illustrating the manner in which the centralizer guides the drill steel during the starting of the drill hole,

Figure 2 is a transverse view taken through Figure 1 on the line 22 looking in the clirect-ion indicated by thearrows,

Figure 3 is an enlarged sectional elevation of the centralizer,

Figure 4 is a plan view of the centralizer,

Figure 5 is an elevation partly in section of a modifiedform of the invention, and

Figure 6 is a plan view of the modification shown in Figure 5.

Referring more particularly to the drawings, A represents a guide such as is used in connection with submarine drilling appa ratus as a mounting for the drill. The guide may be suitably mounted on a barge (not shown) and in this instance is shown as being embedded with its lowermost end in the silt or overburden B which overlies the rock C intended to be drilled.

' i The guide A has afiixedtliereto a hopper D which is suitably flared at its entrance for convenience of inserting the working implement, such as a drill steel E, which extends therethrough. Beneath the hopper D are bearings F and for holding a sand pipe H which is pressed through the silt B and bears with its free end against therock C.

' The function of the sand pipe H is to assure free movement of the drill steel E and also to convey the cuttings from the drill hole to be deposited on the surface of the silt B by 'thewaterused for cleansing the drill hole.

- In accordance with the present invention a centralizer is provided for maintaining the cutting bit of the drill steel E concentric with the pipe This centralizer is in the form of a sleeve 'J of an external diameter slightly smaller than the interior of the sand pipe H. The sleeve J has a bore K therethrough to receive the body portion of the drill steel E and preferably at least one end of the bore K is flared as-at L to correspond to the flared portion 0 of the cutting bitupon which the sleeve J is adapted to'rest. In the periphery of the sleeve J are a plurality of grooves]? which extend longitudinally of the sleeve for conveying detritus from the drill hole rearwardly of the sleeve into the sand pipe.

In ordertopermit the sleeve J to be disposed over the rearward or shank end of the drill steel E particularly where the drill steel is ofthe type having lugs Q for engagement with a rock drill, the sleeve is provided with slots R to permit the passage of the lugs Q,

therethrough. Preferably the slots R are of less length thanthe sleeve and open at their inner ends into a recess S. c

From the recess S to the lowermost end of the sleeve J extend slot-s T which are so located with respect to the slots R that after the sleeve J has been disposed on the drill steel to a point where the lugs Q lie in the recess S the sleeve will have to be turned a partial revolution to on the slots R into alignment wit-h the lugs. his arrangement of the slots will assure an adequate bearing in the sleeve for the body portion of the drill steel E so that irrespective of the position the sleeve may assume on the drill steel, the drill steel will be prevented from moving into the slots and thus creeping out of alignment with respect to the drilling apparatus.

In t e modification illustrated in Figures 5 and 6 the sleeve U is provided in its periphcry with slots V for conveying the detritus rearwardly of the sleeve. The slots V are spiraled so that the sleeve will at all times remain coaxiaLwith the sand pipe H and will therefore be revented from assuming an eceo centric position in the sand pipe as might otherwise occur were only the edges of a slot to bear against the same pipe.

The slots W in the interior of the sleeve U through which the lugs Q are adapted to pass 15 are also spiraled so that the drill steel may at all times bear against a large area of the boreX of the sleeve for holding the sleeve ooneentric with respect to the drill steel.

I claim:

.30 1. In combination with a sand pipe and a drill steel, a drilling bit on the drill steel havi a tapered peripheral surface, a sleeve slidab y disposed about the drill steel and guided by the sand pipe for holding the drill steel ,35 concentric with respect to the sand pipe, said sleeve having a tapered internal surface at its forward end to bear against the tapered surface of the bit, and grooves in the periphery of the sleeve to permit the passage of 0 detritus through the sand pipe.

2. In combination with a sand pipe and a drill steel having lugs, a sleeve having a bore to receive the drill and guided by the sand pipe for maintaining the drill steel concentrio with respect to the sand pipe, longitudinul grooves in theperiphery of the sleeve to conveydetritus therethrough, and slots in the to permit the passage of the lugs through the sleeve, said slots having portions lying in difiemnt longitudinal planes to assure an adeqimte bearing for the drill steel in the bore. z'In testimony whereof I have signed this specification.

CHARLES C. HANSEN. 

